And the cars, intricate and sleek, careened through downtown Baltimore, blazing what many hope is a new tradition in the city's collective life.

The inaugural Baltimore Grand Prix concluded Sunday, impressing spectators, particpants and city officials. Perhaps it was only appropriate that the winner of the race — which followed months of elaborate preparations and traffic-snarling construction — was named Will Power.

Power, who has won more competitions this year than any other driver, gushed that Baltimore's three-day racing festival was "very impressive for the first year."

"They've put on the best race we've had all year," he said of the contest that lasted two hours and two minutes. "This is what Indycar needs."

Although final measures of the race's economic impact, and the cost to the city coffers, could take days or weeks to tally, officials declared the event a success. The Baltimore Police Department estimated that 15,000 attended Friday and 40,000 Saturday. No official count was available Sunday, but organizers estimated that attendance topped 150,000 for the three-day event and said police lowballed crowd counts for the first two days.

Mayor Stephanie Rawlings-Blake, speaking at a news conference after the race, denounced those who had doubted the event's potential.

"The naysayers certainly had their day," she said, then paused for effect, "until the race started."

"Anytime you do something big you take a risk," said Rawlings-Blake. "I had the opportunity to let Baltimore shine."

The city, which invested more than $6.2 million to prepare roads for the event, has inked a tentative five-year contract with Baltimore Racing Development, a group that conceived the city's grand prix. Indycar officials plan to release next year's racing schedule later this month.

Spectators savored the novelty of seeing cars fly through city streets at speeds approaching 190 miles an hour.

"It's just as exciting when they come by for the 70th time as when they went by the first," said Albert Whitelock of Severna Park, who viewed the race from Pratt Street, where cars hit the highest speeds along a long straightaway.

"It never gets old," Whitelock shouted over the roar of the engines. "To have this in Baltimore, it just puts the whole city in a different light."

Steve Thomas weaved through the crowd gripping a unique souvenir — a used tire.

The 21-year-old college student from Westminster picked up the tire from the Baltimore Convention Center, which housed a paddock of race cars, transport trucks and equipment.

The tire was covered with gobs of rubber, which had melted from the heat of the race and congealed again, and emblazoned with a driver's autograph in white ink.

"Honestly, I don't know who it was," said Thomas, a new convert to Indycar racing, pointing to the signature on the tire.

Longtime racing fans said they had grown smitten with the city but felt that race organizers needed to work out a few bugs.

Bob and Sandy Foulkes had driven to Baltimore from their Tabernacle, N.J., home in February to scope out the best spot for seats. Yet, despite all their research, they wound up in a spot where trees blocked their view of the course.

"Our seats are not good," said Sandy Foulkes, explaining seat maps had not shown the trees. "We're kind of hanging off of the grandstands as much as we can."

The couple, clad in the red-and-black insignia of Power's Penske racing team, said they were charmed by their Fells Point hotel and a romantic Saturday evening in Little Italy, but they thought logistical kinks needed to be worked out. The Foulkes said the the lines to enter and exit the grandstands area were longer than other races they had attended.

Like the Foulkes, John Henriques of White Marsh also was looking at trees during the race. But Henriques, president of TGM contracting, viewed the course with a very different mindset — his company had been hired to chop down and later replace trees along the track.

More than 70 trees were removed along the track and pit lanes, touching off a storm of criticism from environmentalists. Henriques' company will soon replant all of those trees, plus scores more, he said. And organizers have pledged to donate 5,000 saplings to the city, he said.

"We're putting them back," Henriques said with a nervous laugh.

Hundreds of police, firefighters and other city employees patrolled the race festival, guiding traffic on temporary pedestrian bridges, treating those overwhelmed by the heat and calming the occasional drunk. Officials did not report any serious incidents.

Police Commissioner Frederick H. Bealefeld III, a lacrosse buff at his first car race, said it was a challenge to essentially shut down "the bottom third of the city" but he said the proof of success will be determined not by the size of the crowd but by whether "the people are safe and having a good time."

"When the cars hit the track, there was a surge of energy through the crowd," said Bealefeld.

His spokesman, Anthony Guglielmi, joked that the city left the speed cameras on. "That's how we'll collect revenue," he said.

The streets outside the race were nearly as packed as those inside, as spectators without tickets angled for a glimpse of the course.

Lamarr Shields, president of an educational consulting company, and his three children, settled on the sidewalk near Pratt and Light Streets. "My son is so excited. He's a Lightning McQueen fan," said Shields, referring to a character in the animated movie "Cars."

Mosiah, 4, darted his head from side to side as he watched the cars zoom by from his stroller.